Update README.md (#204)

Update the readme file with relevant links and fix typos

Co-authored-by: Özgün Özerk <ozgunozerk.elo@gmail.com>

README.md

@@ -1,9 +1,10 @@
 # OpenZeppelin Runtime Templates for Substrate
 
-Substrate has a steep learning curve. In order to make it easier for newcomers to get started, OpenZeppelin is providing runtime templates that can be used to quickly bootstrap a Substrate project.
+[Polkadot SDK](https://github.com/paritytech/polkadot-sdk) has a steep learning curve. In order to make it easier for newcomers to get started, OpenZeppelin is providing runtime templates that can be used to quickly bootstrap a [Substrate](https://github.com/paritytech/polkadot-sdk/tree/master/substrate) project using Polkadot SDK.
 
 Along with the templates, OpenZeppelin also provides a [documentation website](https://docs.openzeppelin.com/substrate-runtimes) that explains the templates and the details.
 
+
 ## About this repository and templates
 
 This repository contains all of our templates. Each template has its own sub-directory, is completely standalone, and can be used independently.
@@ -29,7 +30,8 @@ This template has evm compatibility out of the box. You can migrate your solidit
 
 ### How to use
 
-Please refer to our docs for a `quick start` [guide](https://docs.openzeppelin.com/substrate-runtimes/):
+Please refer to our docs for a `quick start` [guide](https://docs.openzeppelin.com/substrate-runtimes/).
+
 
 ## Security
 

docs/modules/ROOT/pages/index.adoc

@@ -1,7 +1,7 @@
 :source-highlighter: highlight.js
 :highlightjs-languages: bash
 
-= Substrate Parachain Runtimes
+= Polkadot Parachain Runtimes
 
 A collection of runtimes that describe parachains with different purposes.